Cite this article as:
Akdemir Evrendilek, G., Bulut, N., Uzuner, S. (2021). Edible Film Production from Effluents of Potato Industry Incorporated with Origanum
onites Volatile Oils and Changes Its Textural Behaviors under High Hydrostatic Pressure. International Journal of Agriculture, Environment and Food Sciences, 5(4), 580-591
Doi: https://doi.org/10.31015/jaefs.2021.4.18
Orcid: Gulsun Akdemir Evrendilek: https://orcid.org/0000-0001-5064-4195 , Nurullah Bulut: https://orcid.org/0000-0001-9106-8323 , Sibel
Uzuner: https://orcid.org/0000-0003-1050-8206
Received: 20 November 2020 Accepted: 05 September 2021 Published Online: 27 December 2021 Year: 2021 Volume: 5 Issue: 4 (December) Pages: 580-591
Available online at : http://www.jaefs.com - http://dergipark.gov.tr/jaefs
Copyright © 2021 International Journal of Agriculture, Environment and Food Sciences (Int. J. Agric. Environ. Food Sci.)
This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC-by 4.0) License
International Journal of
Agriculture, Environment and Food Sciences
e-ISSN : 2618-5946 DOI: 10.31015/jaefs.2021.4.18
Research Article Int J Agric Environ Food Sci 5 (4):580-591 (2021)
Edible Film Production from Effluents of Potato Industry Incorporated
with Origanum onites Volatile Oils and Changes Its Textural Behaviors
under High Hydrostatic Pressure
Gulsun Akdemir Evrendilek1,* Nurullah Bulut1 Sibel Uzuner2
1 Bolu Abant Izzet Baysal University, Engineering Faculty, Food Engineeeing Department, Bolu, Turkey
2 Izmir Institute of Technology, Engineering Faculty, Food Engineeeing Department, Urla, Turkey
*Corresponding Author: [email protected]
Abstract
Keywords: Edible film, High hydrostatic pressure, Potato industry effluent, Antimicrobial activity,
Textural properties
Introduction
Recent interests have intensified the search for
biodegradable food packaging and edible polymers
(films) to replace plastics or synthetic polymers due
to the growing environmental concerns (Borah et al.,
2017; Lopez-Rubio et al., 2017). The high cost of
biopolymers, on the other hand, makes agricultural
by-products a viable feedstock to produce edible
films or coatings. Different edible films developed
from polysaccharide, protein, and lipid biopolymers
have potential to be considered as food packaging or
coating to enhance food quality and safety (Nandane
and Jain, 2018; Park et al., 2017). Because it carries
advantages of having lower cost, being available,
higher thermoplasticity, and inherent
biodegradability; starch, as the carbohydrate-based
polymers, is one of the most suitable and promising
material for biodegradable, and edible packaging
(Ehiyet et al., 2011).
According to data released by FAOSTAT in
2019, Turkey ranked in the 14th place, with its 4.8
million tons of potato production (Anonymous,
2019). Potato industry produced about 0.16 tons of
solid waste per ton of processed potato such as pulp,
potato wastewater, and peel (Pathak et al., 2018). In
general, waste from potato industry has been utilized
as components of microbial media (Kot et al., 2020)
as well as production of edible film from potato peel
waste (Othman et al., 2017).
Active food packaging is a rapidly developing
food packaging technology actively allowing to
eliminate contamination of foods (De Kruijf et al.,
2002). Active packages are mostly incorporated with
antioxidants, vitamins, antimicrobial agents, or
flavoring agents as biologically active compounds to
increase its functionality (Quintavalla and Vicini,
2002), and thus antimicrobial agents containing
packaging can be as an excellent packaging
alternative to improve the safety of food products.
Development and characterization of edible film incorporated with Origanum onites volatile oil from the
effluents of potato industry, determination of changes on its textural properties of force and elongation at break
(EAB) under high hydrostatic pressure (HHP) in addition to its antimicrobial effect against Escherichia coli
O157:H7 and Salmonella Enteritis were prompted. The optimum operational conditions under HHP for
maximum force and EAB were achieved with 350 MPa pressure, 8 min operational time, and addition of 45
μL O. onites volatile oil concentration (VOC). Inhibition zones for S. Enteritis and E. coli O157:H7 at the
optimum conditions were 1.7 ± 0.109 and 2.386 ± 0.07 cm, respectively. Textural properties of force and EAB
of the HHP-processed films ranged from 2.27 ± 0.52 to 5.23 ± 0.79 N, and from 7.47 ± 1.68 to 15.71 ± 0.65
mm, respectively. Thermal transition of the edible film was observed at 86.77°C for 7.19 min. The microscopic
observation of the film surfaces shoowed homogenous and translucent structure. The improved textural
properties with HHP and VOC revealed that it carries a potential to be used as a food packaging material.
581
G. Akdemir Evrendilek, B. Bulut, S. Uzuner DOI: 10.31015/jaefs.2021.4.18
Essential plant oils of origanum species as
antimicrobial agents are getting more interests
because of their potential antimicrobial properties
and consumer demand for less synthetic and
artificial additives in foods (Ehivet et al., 2011; De
Kruijf et al., 2002; Quintavalla and Vicini, 2002;
Burt, 2004; Min and Oh, 2009).
High hydrostatic pressure (HHP) processing
involves application of high pressures from 100 to
800 MPa to liquid and solid foods at ambient, lower,
and higher than the ambient temperature (Farkas and
Hoover, 2000; Torres and Velazquez, 2005). HHP is
mainly used for food pasteurization, but studies
related to effect of HHP on the buckwheat, tapioca
starch film, and modified amaranth proteins
preparation and its effect on starch gelatinization as
well as film properties were reported (Condés et al.,
2015; Kim et al., 2018). Even though development
of edible films and measurement of their textural and
mechanical properties are reported in the literature,
information regarding the use of food industry by-
products in the development of potential food-
packaging materials, measurement of its properties,
and determination of changes in its properties under
food processing technologies such as HHP when
used as food packaging material is not reported in the
literature. Thus, the objective of this study was to
produce an edible film from effluents of potato
production industry having potential to be food
packaging incorporated with Origanum onites
volatile oil to carry antimicrobial properties and
determine its textural behaviors under HHP.
Materials and Method
Effluents of potato production treatment
plant
Effluents were sampled from a potato processing
plant based in Bolu, Turkey (Köksal Patates Sanayi
ve Ticaret A.Ş.). The samples were taken at the same
day when discharge was started.
Extraction and determination of major
constituents of Origanum onites volatile oil
Dried leaves of Origanum onites were purchased
from local stores (Bolu, Turkey). Leaves (30 g) were
placed in a 2 L-volume Clevenger type apparatus and
mixed with 500 mL water before extraction.
Temperature of the heater was gradually increased
up to 250 oC for 2 h for extraction. Temperature of
the extracted oil was lowered to room temperature
with cooling coils connected to tap water. Obtained
oil was kept in an amber-colored bottle at 4 oC until
its further use (Dadalioglu and Evrendilek, 2004).
In order to determine the major constituents, 30
μL of the O. onites volatile oil were mixed with 1.5
mL hexane before injecting to a gas chromatography
mass spectroscopy (GC-MS) (Shimadzu 2010 QP
2010 Plus GC-MS Kyoto, Japan) coupled with HP-5
MS capillary column (30 m x 0.25 µm x 0.25 µm)
with 250 oC injection block temperature. A
maximum column temperature of 325 oC was used
starting at 50 oC for 5 min, with a 2 oC/min increase
to 90 oC, then a 5 oC/min increase to 210 oC for 5
min. Helium as a carrier gas at a flow-rate of 1.5
mL/min. Mass spectrum of each compound was
taken over the 35–350 m/z range with the electron
ionization mode of 70 eV. Volatile oil components
(VOC) were identified with comparison of their
retention indices (RIs) and mass spectra to Wiley
(275) library (Dadalioglu and Evrendilek, 2004).
Preparation of the edible film
Effluent samples contained pieces of solid potato
particles and peels, thus liquid phase was removed at
room temperature after the samples were settled for
three hours. After removal of macro particles, the
fraction contained starch was centrifuged at 0.45 x g
for 5 min. Pellets from the effluent were dried at 37 oC for 24 h, and grinded with an 8-mm sieve. About
300 g dry residue were obtained from 5 L effluent.
Twenty-five g of dried residue mixed with 250
mL water (1:10 w/v ratio) and 5 % (v/v) plasticizer
(glycerol). The magnetic hot plate (Wisestir,
Germany) at 240 rpm was set to 150 oC, and the
mixture at 85-90 oC was heated for at least 75 min.
pH was adjusted to 2.6 with 0.1M HCl (Sigma
Aldrich, Steinheim, Germany). Food grade green
colorant (0.2 mL) and O. onites volatile oil at three
different concentrations of 30, 45, and 60 µL/mL
were added to edible film mixtures (Table 1). The
mixture solution was stirred until colorant and O.
onites oil are homogenously mixed. The final
solution was cooled at room temperature and poured
into an aluminum casting tray (26 x 17 cm) placed
into a natural convection oven at 40 oC for 10 hours
to dry the film samples.
Bacterial cultures
Activation of Escherichia coli O157:H7 (ATCC
35218) and Salmonella Enteritis (OSU 799) cultures
(The Ohio State University, Columbus, OH) was
realized by transferring both cultures to Tryptic Soya
Broth (TSB, Fluka, Seelze, Germany). Both cultures
were incubated at 35 ± 2 oC overnight. After
transferring grown cells into sterile tubes; the
samples were centrifuged at 0.49 x g for 15 min,
separately, and the supernatants of the liquids were
removed. Obtained pellets were resuspended with 10
mL pre-sterilized phosphate buffered saline (Sigma
Chemical Co., Stockholm, Sweden). Cell
resuspensions were washed with PBS in several
times to remove TSB. Number of viable cells as log
cfu/mL were determined by preparing a 10-fold
serial dilutions of 0.1 mL aliquot plated on TSA
plates. Prepared plated were incubated at 35 ± 2 oC
for 24 h.
High hydrostatic pressure processing
A 2-L capacity pilot-scale HHP equipment
(Avure, Middletown, OH, USA) with water used as
pressured fluid was used to process the film samples.
The pouches were put into the flexible pouches
composed of a multilayer
polymer/aluminum/polymer film (polyethylene–
aluminum–polypropylene) (APACK Packaging
Technologies, Istanbul, Turkey). After heat sealing
of the pouches, the samples were processed by the
pressures changing from 200 to 500 MPa, treatment
time from 1 to 15 min, O. onites volatile oil volumes
(VOC) from 30 to 60 µL (Table 1), and the
maximum processing temperature of 29 oC.
582
G. Akdemir Evrendilek, B. Bulut, S. Uzuner Int J Agric Environ Food Sci 5(4):580-591 (2021)
Properties of the effluent
pH of the effluents was measured at room
temperature with 10 mL of the samples (Orion
perpHectlogR meter, Inolab WTW, Germany).
Conductivity (mS/cm) measurement was
performed by conductivity meter (Sension 5 model,
HACH, CO, USA) with 50 mL of the samples at
room temperature.
Twenty-five mL of the effluent samples at room
temperature was used for turbidity measurement.
Turbidity (NTU) was conducted by the turbidimeter
(Micro TPI, HF Scientific, FL, USA).
Fifty mL of the samples after filtration through
Whatman 42 filter paper dried at 105 oC for 30-40
min. Suspended solid matter (SSM) was calculated
by taking into account the initial weight (g) of the
paper after drying (A) and the weight (g) of the paper
after filtration (B) (Rice et al., 2005).
𝑆𝑆𝑀 (𝑚𝑔
𝐿) =
(𝐵−𝐴)
𝑉𝑥100 (1)
Spectroquant cell tests (DIN ISO 15705, Merck,
Germany) were used to determine chemical oxygen
demand (COD). The effluent samples were
homogenized, and then diluted with distilled water
at 1:50 ratio. Three mL of the diluted samples were
taken and placed into the COD tubes heated at 148 oC in thermoreactor for 120 min. When the tubes
were cooled to room temperature, the measurement
was performed using the photometer.
Initial microbial load of effluent
Appropriate dilutions of effluent samples
prepared with 0.1 % peptone were plated onto potato
dextrose agar (PDA, Fluka, Seelze, Germany) to
count total mold and yeast count (TMY); and plate
count agar (PCA, Fluka, Seelze, Germany) to count
total aerobic mesophilic bacteria (TAMB),
respectively. PCA plates were incubated at 35 ± 2 oC
for 24 to 48 h, while PDA plates were incubated
at 22 ± 2 oC for 3 to 5 days. Results were expressed
in log cfu/mL.
Properties of the edible film
Weight and thickness of edible films cut in an
8.64-mm diameter using a mold were measured
using a balance with 0.001 g sensitivity and
micrometer (Mitutoyo, Japan) with 0.0001 mm
sensitivity, respectively (Seydim and Sarikus, 2006).
Edible films were cut at 40 x 40 mm2 dimensions,
and each piece was transferred into beaker
containing 50 mL of water for the determination of
water solubility. Each beaker was sealed with
parafilm and they were transferred into shaking
water bath at 25 oC for 24 h. Insoluble fraction of the
film samples was dried at 70 oC for 10 min until a
constant weight was reached. Results were
calculated as follows (Razavi et al., 2015):
% 𝑤𝑎𝑡𝑒𝑟 𝑠𝑜𝑙𝑢𝑏𝑖𝑙𝑖𝑡𝑦 =𝑊0−𝑊24
𝑊0∗ 100
(2)
where W0 is the initial dry weight of the film
before drying (g), while W24 is the final dry weight
(g) of the insoluble film after drying.
L*, a*, and b* color parameters of the edible film
were measured using a colorimeter (Konica Minolta
CR-400, Osaka, Japan) Total color difference
(∆𝐸) was calculated as follows;
∆𝐸 =
√(𝐿0 − 𝐿 ∗)2 + (𝑎0 − 𝑎 ∗)2 + (𝑏0 − 𝑏 ∗)2 (3)
Both the control and the HHP treated films
samples having O. onites volatile oil were cut in 80
x 25 mm dimensions using a standard mold at 25 oC
and 53 ± 2% relative humidity for 48 h before
textural measurements. Elongation at break (EAB)
and force of the film samples were measured using a
TA-XT2 model texture analyzer (Stable Micro
Systems, Surrey, England) with a tensile grip at 1
mm/s speed, and calculated by the software (Texture
Table 1. (Un)coded variables of Box-Behnken design for textural properties of biopolymer with Origanum
onites volatile oil.
Run
Order
HHP pressure
(P, MPa)
X1
Volatile oil
concentration
(VOC, μL) X2
Time
(T, min)
X3
Force
(N)
Elongation at
break (mm)
Control - - - 3.60 ± 0.23bc 8.83 ± 0.14d
1 500 45 1 4.57 ± 0.07a 11.78 ± 1.35b
2 500 60 8 4.90 ± 0.60a 15.71 ± 0.65a
3 350 30 1 5.23 ± 0.79a 12.53 ± 0.62b
4 200 60 8 4.64 ± 0.51a 10.25 ± 1.09c
5 500 45 15 3.79 ± 0.26bc 12.79 ± 1.49b
6 200 30 8 4.70 ± 0.39a 12.71 ± 2.72bc
7 350 45 8 4.43 ± 0.28ab 9.82 ± 1.20c
8 200 45 15 2.27 ± 0.52d 7.47 ± 1.68e
9 500 30 8 4.68 ± 0.16a 10.78 ± 1.13c
10 350 30 15 3.95 ± 0.08c 12.67 ± 1.33bc
11 350 60 1 3.92 ± 0.54b 12.49 ± 1.65bc
12 200 45 1 2.68 ± 0.01 9.04 ± 0.00d
13 350 60 15 3.85 ± 0.39 12.30 ± 2.46b
*Data with different superscript letters in the same response column show a significant difference at p ≤ 0.05.
**Data is presented as average ± standard deviation
583
G. Akdemir Evrendilek, B. Bulut, S. Uzuner DOI: 10.31015/jaefs.2021.4.18
Expert Exceed 2.3, Stable Micro System, Survey,
England) (Chaichi et al., 2017).
Thermal properties of edible film
Differential scanning calorimeter (DSC, TA Q20
Instruments, Shimadzu, Japan) was used in order to
determine the thermal properties of biopolymers.
Calibration was performed with the indium standard
(156.6 oC melting temperature and 28.5 J/g melting
enthalpy) under the nitrogen atmosphere with 30
mL/min flow rate. Thermograms were obtained with
2-3 mg of the samples weighed into sampling cups,
and scanning was made between 20 and 100 oC at an
interval of 10 oC/min.
Surface properties of biopolymer was observed
using a binocular microscopy (BK 5000 L modal,
Soif Optical Instruments, China) at 4x
magnification. X-ray diffraction (XRD) patterns of
the films were measured using a MRD X-ray
diffractometer (Rigaku, Neu-Isenburg, Germany)
with Coka radiation. The samples were prepared by
placing the square shape of each film (2 cm x 2 cm)
on a glass side. A nickel monochromator filtering
wave was used at 36 kV and 26 mA with scanning at
2ϴ = 50- 800 at a rate of 2.200/min and with a step
size of 0.020.
Antimicrobial activity of edible film
Antimicrobial activity of the edible film was
tested against S. Enteritis and E. coli O157:H7,
separately. Both cultures at the 106 cfu/mL cell count
were plated onto PCA agar plates, and the plates
were incubated for 48 h at 35 ± 2 oC for surface
growth. An edible film disc of 8.64 mm with 45 µL
O. onites volatile oil (concentration at optimum
point) added during film preparation was placed onto
surface of PCA agar. The plates were incubated for
additional 24 h at 35 ± 2 oC, and zone of inhibition
was measured using a micrometer. Control samples
were prepared the same but without addition of O.
onites volatile oil.
Data analyses
The force and EAB responses of the edible film
production were optimized as a function of pressure
(200 to 500 MPa), volatile oil concentration (30 to
60 μL), and processing time (1 to 15 min) using the
Box-Behnken design (BBD) with a quadratic model.
The levels of these settings were determined by
initial experiments. The overall BBD configuration
with its (un)coded predictors is presented in Table 1.
Data analyses were conducted by MINITAB 17.0
(Minitab Inc. State College, PA, USA). A quadratic
regression model was used to best-fit the
experimental data:
Yn = b0 + b1X1 + b2X2 + b3X3 + b12X1X2 +b13X1X3
+ b23X2X3 + b11X12 + b22X2
2 + b33X32
(4)
where Yn is the response variable of force and
EAB; b0 to b33 are slope coefficients; and X1, X2 and
X3 are pressure (MPa), VOC (µL), and processing
time (sec), respectively. Additional experiments, to
validate the models, were carried out under the
optimal conditions. Analysis of variance (ANOVA)
and regression models were applied to determine the
significant terms of the predictive model (p < 0.05).
Tukey’s test was further utilized to determine the
multiple comparisons. Verification of the predicted
model was conducted by the coefficient of variation
(CV, %) as follows:
100
=
CV (5)
where is sample standard deviation, and C is
sample mean.
Results and Discussion
Properties of the effluent and the edible film
The effluent samples had pH of 6.16 ± 0.14,
conductivity of 1774 ± 38 mS/cm, and turbidity of
1170.00 ± 57.01 NTU at the temperature of 12.49 ±
0.34 oC. The mean COD was determined as
50093.75 ± 3361.41 mg/L. The amount of SSM was
0.65 ± 0.13 mg/mL. The initial TMAB and TMY
loads were > 9 log cfu/mL.
Average weight and the thickness of the film
samples were 0.0177 ± 0.0004 g and 0.370 ± 0.005
mm, consequently. Water solubility of the edible
film was estimated at 32.69 ± 4.34%. The color of
the edible film changed from cream to green with the
addition of green coloring agent. The natural color of
the edible film before addition of green color was
measured as 79.55 ± 0.64, -0.0011 ± 0.01, and 4.19
± 0.18 for L*, a*, and b*; whereas they were
measured as 76.8 ± 1.84, -21.70 ± 4.92, and 28.94 ±
4.77 after addition of green color, respectively. ΔE
of the edible film samples were recorded as 84.89 ±
11.36.
The initial force and EAB values of the film were
3.60 ± 0.23 N and 8.83 ± 0.14 mm, respectively.
With HHP treatment, the force ranged from 2.27 ±
0.52 to 5.23 ± 0.79 N. Except for run 8 (200 MPa
pressure, 45 µL volatile oil, and 15 min treatment
time) and run 12 (200 MPa pressure, 45 µL volatile
oil, and 11 min treatment time), HHP treatments
regardless of the processing time and VOC, led to
higher force values than that of the control samples
(p ≤ 0.05). The highest VOC (60 µL) and pressure
(500 MPa) under the moderate processing time (8
min) provided the highest force to film (5.23 ± 0.79
N) on run 3 (p ≤ 0.05) (Table 1).
EAB of the HHP-treated samples ranged from
7.47 ± 1.68 to 15.71 ± 0.65 mm. Except for run 8
with (200 MPa pressure, 45 µL volatile oil, and 15
min treatment time), all the other HHP processes
revealed higher EAB value than that of the control
samples. Again, the highest VOC (60 µL) and the
pressure (500 MPa) under the moderate processing
time (8 min) provided the highest EAB (15.71 ± 0.65
mm) on run 2 (p ≤ 0.05). The increased force did not
linearly increase with the VOC and processing time,
but with the pressure and the combination of
pressure and VOC (Table 1).
Inhibition zone diameters of S. Enteritis and E.
coli O157:H7 with the addition of 45 mL volatile O.
onites oil were 1.70 ± 0.109 and 2.39 ± 0.07 cm with
the calculated inhibition zone area of 2.15 ± 0.383
and 4.95 ± 0.341 cm2, respectively. No zone of
584
G. Akdemir Evrendilek, B. Bulut, S. Uzuner Int J Agric Environ Food Sci 5(4):580-591 (2021)
inhibition was observed for the edible film samples
with no O. onites volatile oil.
GC-MS analyses of O. onites volatile oil
revealed 76 different compounds among which 5-
methyl-2-propan-2-ylphenol (thymol, 34.67%), 2-
methyl-5-(propan-2-yl) phenol (carvacrol, 28.32%),
3-methylpentane (5.65%), 3,7-dimethylocta-1,6-
dien-3-ol (linalool 5.06%), 1-methyl-4-(propan-2-
yl) benzene (p-cymene, 3.48%), and 2-
methylpentane (2.22%), were the highest. High
antibacterial activity of O. onites volatile oil
correlated with the important percentages of thymol
(34.67%) and carvacrol (28.32%). Both constituents
were also found higher in O. onites samples by 5.97
and 71.22% (23) and 1.51 and 37.08% (Sevindik et
al., 2019). The ability of origanum species to
inactivate bacterial strains in synthetic media as well
as in food system were related to higher amount of
both thymol and carvacrol (Lambert et al., 2001;
Knowles et al., 2005; Valero and Francés, 2006). It
is also reported that not only the components present
in high proportions are responsible for the
antimicrobial activity, but also the less abundant
ones, like p-cymene should also be considered.
Aqueous extract of O. onites displayed MIC value of
25 mg/mL against methicillin susceptible
Staphylococcus aureus (MSSA), methicillin
resistant S. aureus (MRSA), Klebsiella pneumoniae,
Pseuodomonas aeruginosa, Bacillus cereus, and
Enterococcus faecalis, and 6.25 mg/mL against E.
coli (28). Indeed, it was also presented that
carvacrol, thymol and p-cymene of O. compactum
essential oil have strong antibacterial affect against
different bacteria (Andrade-Ochoa et al., 2015;
Bouyahya et al., 2017; Chauhan and Kang, 2014; Li
and Liu, 2009; Xu et al., 2008).
Starch based active films and food packaging
with the addition of plasticizers is a promising
alternative due to their low cost, availability and
functionality (Castillo et al., 2017). Antimicrobial
properties of these films make them suitable for food
packaging providing significant inactivation of food
borne pathogens and food spoilage microorganisms.
For instance, tapioca starch-glycerol edible films
incorporated with potassium sorbate controlled
growth of Zygosaccharomycess bailii contamination
in semisolid product (Flores et al., 2007). Starch-clay
nanocomposite films contained potassium sorbate
presented antimicrobial property against Aspergillus
niger (Barzegar et al., 2014). Starch film having
different concentrations of chitosan and lauric acid
exert an inhibitory effect on Bacillus subtilis and E.
coli growth (Salleh et al., 2014).
Due to the antimicrobial properties of Maillard
compounds, 1-2 log inactivation was observed on
Listeria innocua and E. coli inoculated in starch
based edible film from corn formulated with
different oxidation degree and addition of bovine
gelatin, glycerol, as a plasticizer, and ethyl lauroyl
arginate (LAE) as antimicrobial compound (Moreno
et al., 2017). Inhibition efficiency of the starch films
incorporated with tea polyphenol (TP) ranged
approximately from 60 to 90% for E. coli and from
90 to 100% for S. aureus revealing good
antimicrobial properties (Feng et al., 2018).
It is desired for edible films to have high water
resistance because they can be used as protective
layers on high as well as intermediate moisture foods
(Gontard et al., 1992). In order to prevent the
complete dissolution of the film, corporation of
antimicrobial agents into edible films are also
desired. Antimicrobial edible films having poor
water resistance is dissolved very quickly, thus its
antimicrobial properties protected (Castillo et al.,
2017; Ozdemir and Floros, 2008). Water solubility
of the buckwheat starch film prepared using thermal
processing (90 oC for 20 min) and HHP (600 MPa 20 oC for 20 min) were 19.85 and 11.67%, respectively.
It was observed that the water solubility of both films
decreased with the application of HHP in spite of the
higher moisture content (Kim et al., 2018). The
water solubility of the edible film developed in the
present study was comparable to those cited in the
literature (Kim et al., 2018).
Thermal properties of the edible film
Thermogram results showed that the thermal
transition of the edible film was at 86.77 °C for 7.19
min. No activity recovered from the samples after
thermal transition temperature indicated that the
phase transition was irreversible.
Thermal degradation behavior and stability of
starch based materials is important property because
it determines the behavior of the film during
processing (Liu et al., 2013). Thermo-gravimetric
analysis has been widely used to determine the
thermal stability and decomposition of starch based
film formulated using different sources (Aggarwal et
al., 1996; Guinesi et al., 2006; Soares et al., 2005).
Both dehydration and decomposition are taken into
consideration with the degradation mechanisms of
starch (Liu et al., 2009; Liu et al., 2013). These
values give information to predict how these
materials behave under more realistic atmospheric
conditions (Acar et al., 2008; Peterson et al., 2001).
Thermal properties of the film change depending
on the base materials and type of the plasticizers
used. For example, sage seed gum (SSG) edible
films with glycerol and sorbitol presented two
exothermic peaks with Tg at about 59.7 and 277.7 °C,
which the latter may be related to the thermal
decomposition of SSG. Tg of SSG film shifted to
52.2 and 179.1 °C with the presence of glycerol,
while sorbitol reduced it to 47.2 and 245.3 °C,
respectively. In the glycerol plasticized sample, two
additional peaks with Tg of about 286.4 and 340.8 °C
were appeared (Razavi et al., 2015).
The microscopic observation of the film surfaces
showed that the film was homogeneous and
translucent. Even though film formation occurred
due to the solubility of starch molecules, some starch
molecules were still intact and not completely
soluble (Figure 1a). Water-based green color was
dissolved in the film and distributed in the
continuous starch matrix. HHP processing caused
swelling of starch molecules and led to the even
distribution of green color (Figure 1b). Starch
585
G. Akdemir Evrendilek, B. Bulut, S. Uzuner DOI: 10.31015/jaefs.2021.4.18
molecules grew in size and were dissolved better
after the HHP processing (Figure 1c).
a) Control film
samples (4X
magnification)
b) O. onites
volatile oil added film
samples (4X
magnification)
c) Origanum
onites volatile oil
added and HHP
processed (200MPa 1
min) film samples (4X
magnification)
Figure 1. Microscopic observations of the film
samples
Pressure application provides gelatinization of
starch in two steps: At first stage, hydration of the
amorphous parts of the starch granules occur, and
then crystalline region starts to swell (Grossi et al.
2012; Simonin et al., 2011). Applied pressure level,
model of pressure application (continuous or cycle),
pressure time, processing temperature, as well as the
constituent and phase state of the food affect the
resistance of starch microstructure to pressure
(Simonin et al., 2011). These structural changes after
the HHP treatment helped to understand the changes
in the textural properties of the film. Depending on
the applied HHP processing and VOC
concentrations, the texture of the film changed, thus
affecting the force and elongation properties
It is reported that HHP caused a decrease in
molecular order revealing higher amylopectin
amorphous layer (ρa) (unlikely), or induced changes
in both crystalline and amorphous regions leading to
ρa decrease (Lopez-Rubio et al., 2017). Applied
magnitude of pressure plays an important role in
starch structure depending on the starch type. For
example, pressure at the magnitude of 200 MPa does
not cause a noticeable shifts or changes in the main
peaks, but pressure application at 600 MPa for 30
min significantly reduced the peak intensity at 18 °.
Dual peaks observed at 17° and 18° were merged
into a single peak at 17°, characteristic of B-type
starches after the application of 600 MPa at cycle
mode. Due to their scattered and flexible
amylopectin branching structure, A-type starches are
generally believed to be more sensitive to pressure
than B- and C-type ones (Deng et al., 2014).
Table 2. ANOVA and regression model results for two functional responses of biopolymer film with Origanum
onites volatile oil.
Term
Force (g) (Y1) Elongation (mm) (Y2)
Coeff p Coeff p
Linear
P (X1) 55.20 0.000 1.45 0.000
VOC (X2)
T (X3)
Square
P2
VOC2 43.70 0.003 2.35 0.000
T2 -79.50 0.000
Interaction
P*VOC 41.70 0.003 1.85 0.000
P*T -26.50 0.049
VOC*T
Lack-of-fit 0.249 0.616
Intercept 442.7 0.000 10.076 0.000
R2adj 0.77 0.68
Table 3. Summary of experimental versus predicted values for textural properties of biopolymer film according to
BBD.
Force (Y1) Elongation (Y2)
Predicted values 366.87 12.83
Experimental values 368.06 ± 7.31 12.85 ± 0.08
Coefficient variation (CV, %) 0.16 0.07
586
G. Akdemir Evrendilek, B. Bulut, S. Uzuner Int J Agric Environ Food Sci 5(4):580-591 (2021)
00203 0
004
0.01
5.21
2 00240
30005
50
40
60
5.01
tion (mm)agnolE
elitaloV o .cnoc li
)aPM(ressure P
Pressure (MPa)
Vola
tile
oil c
onc.
500450400350300250200
60
55
50
45
40
35
30
>
–
–
–
–
–
–
< 9
9 10
10 11
11 12
12 13
13 14
14 15
15
(mm)
Elongation
Time (min) 8
Hold Values
030004
004
450
05 0
2200030
30005
50
40
30
06
505
FORCE (g)
elitaloV o .cnc lio
)aPM(resP sure
Time (min) 8
Hold Values
Pressure (MPa)
Vola
tile
oil c
onc.
500450400350300250200
60
55
50
45
40
35
30
>
–
–
–
–
< 400
400 440
440 480
480 520
520 560
560
FORCE (g)
Pressure (MPa) 350
Hold Values
10
350
004
0
450
05
10 3015
05
40
30
06
450
05 0
ORCE (g)F
elitaloV .cnoc lio
T )ime (min
Pressure (MPa) 350
Hold Values
Time (min)
Vola
tile
oil c
onc.
1412108642
60
55
50
45
40
35
30
>
–
–
–
–
–
< 380
380 400
400 420
420 440
440 460
460 480
480
FORCE (g)
Volatile oil conc. 45
Hold Values
01
003
400
005
01 00251
004
003
002
500
0
005
)g( ECROF
)aPM( erusserP
)nim( emiT
Volatile oil conc. 45
Hold Values
Time (min)
Pre
ssu
re (
MP
a)
1412108642
500
450
400
350
300
250
200
>
–
–
–
–
< 300
300 350
350 400
400 450
450 500
500
FORCE (g)
a b
d c
f
e
g h
Figure 2. Interaction effects of pressure-volatile oil concentration with treatment time as constant
value on elongation for textural properties of biodegradable film showing a) response surface and
b) contour plots; interaction effects of pressure-volatile oil concentration on force for textural
properties of biodegradable film showing c) response surface and d) contour plots; interaction
effects of time-volatile oil concentration on force for textural properties of biodegradable film
showing e) response surface and f) contour plots; interaction effects of pressure-time on force for
textural properties of biodegradable film showing g) response surface and h) contour plots
587
G. Akdemir Evrendilek, B. Bulut, S. Uzuner DOI: 10.31015/jaefs.2021.4.18
Modelling of the textural properties of the
edible film
Among the three explanatory variables, only
HHP significantly affected (p ≤ 0.05) both force and
EAB of the edible film. According to the best-fit
regression models, there existed a positive
correlation between pressure and VOC (p ≤ 0.001)
for both textural properties (Table 2).
The significant quadratic terms were found for
time (p = 0.000) and VOC (p = 0.003) with a positive
effect on force and VOC (p = 0.000) for EAB of the
film with a negative effect (Table 2). There was a
significant interaction between VOC and pressure (p
≤ 0.05) with a positive effect, and between time and
pressure (p ≤ 0.05) with a negative effect on force. A
significant interaction between pressure and VOC (p
≤ 0.05) with a positive effect on EAB of the film was
also observed (Table 2). The degree of influence of
the operational conditions on the force and
elongation responses can be inferred from
comparing the magnitudes of the coefficients of the
quadratic regression models. HHP was the most
important factor for both force (55.20) and EAB
(1.45) (Table 2). The goodness-of-fit (R2adj) of the
models showed 0.77 and 0.68 % of variations in
force and EAB, respectively (Table 2). The
insignificant lack-of-fit values for the two models
also indicated that the model fitted the experimental
data well (Table 2).
According to ANOVA results, the insignificant
terms were excluded from the models of the textural
properties of the film. The best-fit regression models
explained 81 and 71% of variations in force and
EAB, respectively. The EAB estimates of the film as
a function of HHP, time and VOC are illustrated in
Figure 2a. EAB increased with the increased VOC
under the highest pressure at an increasing rate
(Figure 2a). The highest VOC maximized EAB at
the highest HHP of 500 MPa (Figure 2a). Force
decreased with the increased VOC under the lowest
pressure at a decreasing rate (Figure 2c). The lowest
VOC values minimized force at the constant
pressure of 350 MPa (Figure 2e). The lowest time
minimized force at the lowest pressure (200 MPa)
(Figure 2g). Three-dimensional (3D) response
contour plots were used to observe the interaction
effect of variables in pairs on both EAB and force
(Figures 2a, 2c, 2e, 2g).
While circular contour plots indicate a negligible
interaction, elliptical or saddle contour plots indicate
a significant interaction between the corresponding
variables (Murthy et al., 2000). In both figure 2b and
2d, the contour plot showed a significant interaction
between VOC and HHP. In figures 2f and 2h, the
circular shape of the contour plots indicated a
negative time-by-HHP and a negligible time-by-
VOC interaction for the force of the film.
Joint optimization and model validations
The overlaid contour plots were used to visualize
how the operational settings simultaneously
influenced the force and EAB of the film (Figure 3).
The solid contour line is the lower bound and the
dotted contour is the upper bound (Figure 3). The
contours of each response are displayed in a different
color. The white area of the plots (feasible region)
shows the range of pressure, VOC, and time where
the criteria for three response variables are satisfied
whereas the shaded area shows regions do not fit the
optimization conditions (Figure 3). Figure 3a shows
that VOC at 45μL, the HHP range of 200 to 400 MPa
with 350 MPa of optimum pressure and 1.7 min for
processing time were the optimum setting. With 8
min, both HHP and VOC were maintained in a very
narrow range as shown in figure 3b. The two feasible
zones (Figure 3c) were obtained with the optimum
settings of both time and VOC.
Figure 3. Overlaid contour plots showing feasible
operational regions to maintain textural properties of
biodegradable film under the constant values of (a)
VOC of 45μL, (b) time of 8 min and (c) HHP
pressure of 350 MPa
a
b
c
588
G. Akdemir Evrendilek, B. Bulut, S. Uzuner Int J Agric Environ Food Sci 5(4):580-591 (2021)
The operational settings for force and EAB of the
film production revealed the best solution for the
multiple response optimization with 350 MPa
pressure, 45 μL VOC, and 8 min operational time.
The minimum force (366.87 g) and maximum EAB
(12.83 mm) values were obtained with the optimum
operational conditions. These conditions were
experimentally tested to validate the predictive
power of the models. The resultant force and EAB
values of 368.06 ± 7.3 g and 12.85 ± 0.08 mm,
respectively, indicated no significant difference
between the measured and predicted values (Table
3). The smaller CV values showed the better
reproducibility of the model.
Conclusions
Although different food industry wastes were
used to produce edible films, the production of an
edible film from the effluents of potato industry
carrying antimicrobial properties with addition of O.
onites, measurement of its physical properties, and
determination of the changes in mechanical
properties under HHP are limited. The edible film
produced from the effluents of a potato industry was
HHP-processed (up to 500 MPa) with the addition of
volatile O. onites oil. The combination of O. onites
and HHP-processing provided antimicrobial activity
against both E. coli O157:H7 and S. Enteritis with
2.386 ± 0.07 and 1.7 ± 0.109 cm of inhibition zones
and 4.95 ± 0.341 and 2.153 ± 0.383 cm2 of the
calculated inhibition zone areas, respectively. HHP
significantly affected both force and EAB of the
edible film with a positive correlation between
pressure and VOC for both textural properties. The
optimum operational conditions obtained for the
multiple response optimization were achieved with
350 MPa pressure, 45 μL VOC, and 8 min
operational time.
This study focused on the production of the
edible film from the effluents of potato industry, and
its textural properties and antimicrobial activity. Its
flexible and durable structure showed that this film
may have potential to be applied as a food
packaging, but food-safety, barrier properties, and
migration test must be performed in order to evaluate
its potential as food packaging. Thus, future studies
remain to be conducted to determine the
effectiveness of the film on the shelf life extension
of different foods.
Compliance with ethical standards
Conflict of interest
The authors have no conflict of interest to declare
Author contribution
Gulsun Akdemir Evrendilek: Supervision,
conceptualization, methodology, writing manuscript
& editing, data analyses, project administration,
funding acquisition; Nurullah Bulut: Data curation,
experimental; Sibel Uzuner: Writing manuscript &
editing, data analyses, editing.
All the authors read and approved the final
manuscript. Text, figures, and tables are approved by
all thr authors and they have not been published
before.
Ethical approval
Not applicable.
Funding
Funding for this study was provided by the Scientific
Research Project Unit of Bolu Abant Izzet Baysal
University (Grant no: BAP- 2018.09.04.1304). The
authors would like to thank Republic of Turkey
Ministry of Development Government Planning
Agency (Project no: 2009 DPT K 120140) for
financial support
Data availability
Data will be available upon request.
Consent for publication
Not applicable
Acknowledgement
Our special thanks go to Dr. Nevin Soylu for her help
with XRD analyses and YENIGIDAM Research
Center for GC-MS analyses and HHP runs.
References
Acar, I., Pozan, G.S., Ozgumus, S. (2008). Thermal oxidative degradation kinetics and thermal properties of poly
(ethylene terephthalate) modified with poly (lactic acid). Journal of Applied Polymer Science, 109: 2747–
2755. Doi: https://doi.org/10.1002/app.28142
Aggarwal, P., Dollimore, D. (1996). A comparative study of the degradation of different starches using thermal
analysis. Talanta, 43: 1527–1530. Doi: https://doi.org/10.1016/00399140(96)01930-3
Andrade-Ochoa, S., Nevárez-Moorillón, G.V., Sánchez-Torres, L.E., Villanueva-García, M., Sánchez-Ramírez,
B.E., Rodríguez-Valdez, L.M., Rivera-Chavira, B.E. (2015). Quantitative structure-activity relationship
of molecules constituent of different essential oils with antimycobacterial activity against Mycobacterium
tuberculosis and Mycobacterium bovis. BMC Complementary Medicine and Therapies, 15(1): 332-343.
Doi: 10.1186/s12906-015-0858-2.
Anonymous. (2019). https://www.potatopro.com/world/potato-statistics. (Accessed on 13.03.2019)
Azcan, N., Kara, M., Asilbekova, D.T., Ozek, T., Baser, K.H.C. (2000). Lipids and essential oil of Origanum
onites. Chemistry of Natural Compounds, 36(2):132-136.
Barzegar, H., Azizi, M.H., Barzegar, M., Hamidi-Esfahani, Z. (2014). Effect of potassium sorbate on antimicrobial
and physical properties of starch-clay nanocomposite films. Carbohydrate Polymer, 110: 26-31. Doi:
https://doi.org/10.1016/j.carbpol.2014.03.092
Borah, P.R., Das, P., Badwaik, L.S. (2017). Ultrasound treated potato peel and sweet lime pomace based
biopolymer film development. Ultrasonic Sonochemistry, 36: 11-19. Doi:
https://doi.org/10.1016/j.ultsonch.2016.11.010
589
G. Akdemir Evrendilek, B. Bulut, S. Uzuner DOI: 10.31015/jaefs.2021.4.18
Bouyahya, A., Dakka, N., Talbaoui, A., Et-Touys, A., El-Boury, H., Abrini, J., Bakri, Y. (2017). Correlation
between phenological changes, chemical composition and biological activities of the essential oil from
Moroccan endemic Oregano (Origanum compactum Benth). Indian Crop Production, 108 : 729–737. Doi:
https://doi.org/10.1016/j.indcrop.2017.07.03
Burt, S. (2004). Essential oils: Their antibacterial properties and potential applications in foods-a
review. International Journal of Food Microbiology, 94(3): 223-253. Doi:
https://doi.org/10.1016/j.ijfoodmicro.2004.03.022
Castillo, L.A., Farenzena, S., Pintos, E., Rodríguez, M.S., Villar, M.A., García, M.A., López, O.V. (2017). Active
films based on thermoplastic corn starch and chitosan oligomer for food packaging applications. Food
Packaging and Shelf Life, 14: 128-136. Doi: https://doi.org/10.1016/j.fpsl.2017.10.004
Chaichi, M., Hashemi, M., Badii, F., Mohammadi, A. (2017). Preparation and characterization of a novel bionano
composite edible film based on pectin and crystalline nanocellulose. Carbohydrate Polymer, 157, 167-
175. Doi: https://doi.org/10.1016/j.carbpol.2016.09.062
Chauhan, A.K., Kang, S.C. (2014). Thymol disrupts the membrane integrity of Salmonella ser. Typhimurium in
vitro and recovers infected macrophages from oxidative stress in an ex vivo model. Research in
Microbiology, 165(7): 559–565. Doi: https://doi.org/10.1016/j.resmic.2014.07.001
Condés, M.C., Añón, M.C., Mauri, A.N. (2015). Amaranth protein films prepared with high-pressure treated
proteins. Journal of Food Engineering, 166: 38-44. Doi: https://doi.org/10.1016/j.foodhyd.2015.01.026
Dadalioğlu, I., Evrendilek, G.A. (2004). Chemical compositions and antibacterial effects of essential oils of
Turkish oregano (Origanum minutiflorum), bay laurel (Laurus nobilis), Spanish lavender (Lavandula
stoechas L), and fennel (Foeniculum vulgare) on common foodborne pathogens. Journal of Agriculture
and Food Chemistry, 52: 8255-8260. Doi: https://dio.org/10.1021/jf049033e
De Kruijf, N., van Beest, M., Rijk, R., Sipilainen-Malm, T., Paseiro Losada, P., De Meulenaer, B. (2002). Active
and intelligent packaging: applications and regulatory aspects. Food Additives and Contaminants, 19:
144–62. Doi: https://doi.org/10.1080/02652030110072722
Deng, Y., Jin, Y., Luo, Y., Zhong, Y., Yue, J., Song, X., Zhao, Y. (2014). Impact of continuous or cycle high
hydrostatic pressure on the ultrastructure and digestibility of rice starch granules. Journal of Cereal
Science, 60: 302-310. Doi: https://doi.org/10.1016/j.jcs.2014.06.005
Ehivet, F.E., Min, B., Park, M.K., Oh, J.H. (2011). Characterization and antimicrobial activity of sweet potato
starch‐based edible film containing origanum (Thymus capitatus) oil. Journal of Food Science, 76(1):
178-184. Doi: https://doi.org/10.1111/j.1750-3841.2010.01961.x
Farkas, D.F., Hoover, D.G. (2000). High pressure processing. Journal of Food Science, 65: 47-64. Doi:
https://doi.org/10.1111/j.1750-3841.2000.tb00618.x
Feng, M., Yu, L., Zhu, P., Zhou, X., Liu, H., Yang, Y., Zhou, C., Gao, C., Bao, X., Chen, P. (2018). Development
and preparation of active starch films carrying tea polyphenol. Carbohydrate Polymers, 196: 162-167.
Doi: https://doi.org/10.1016/j.carbpol.2018.05.043
Flores, S., Haedo, A.S., Campos, C., Gerschenson, L. (2007). Antimicrobial performance of potassium sorbate
supported in tapioca starch edible films. European Food Research Technology, 225(3-4): 375–384. Doi:
https://doi.org/10.1007/s00217-006-0427-5
Gontard, N., Guilbert, S., Cuq, J.-L. (1992). Edible wheat gluten films: Influence of the main process variables on
film properties using response surface methodology. Journal of Food Science, 57: 190-195,199. Doi:
https://doi.org/10.1111/j.1365-2621.1992.tb05453.x
Grossi, A., Søltoft-Jensen, J., Knudsen, J.C., Christensen, M., Orlien, V. (2012). Reduction of salt in pork sausages
by the addition of carrot fibre or potato starch and high pressure treatment. Meat Science, 92: 481-489.
Doi: https://doi.org/10.1016/j.meatsci.2012.05.015
Guinesi, L.S., da Roz. A.L., Corradini, E., Mattoso, L.H.C., Teixeira, E.D.M., Curvelo, A.A.D.S. (2006). Kinetics
of thermal degradation applied to starches from different botanical origins by non-isothermal procedures.
Thermochimica Acta 447: 190–196. Doi: https://doi.org/10.1016/j.tca.2006.06.002
Kim, S., Yang, S.Y., Chun, H.H., Song, K.B. (2018). High hydrostatic pressure processing for the preparation of
buckwheat and tapioca starch films. Food Hydrocolloids, 81: 71-76. Doi:
https://doi.org/10.1016/j.foodhyd.2018.02.039
Knowles, J.R., Roller, S., Murray, D.B., Naidu, A.S. (2005). Antimicrobial action of carvacrol at different stages
of dual-species biofilm development by Staphylococcus aureus and Salmonella Enterica serovar
Typhimurium. Applied and Environmental Microbiology, 71(2) : 797–803. Doi: https://doi.org
/10.1128/AEM.71.2.797-803.2005
Kot, A.M., Pobiega, K., Piwowarek, K., Kieliszek, M., Błażejak, S., Gniewosz, M., Lipińska, E. (2020).
Biotechnological methods of management and utilization of potato industry waste-a Review. Potato
Research, 1-17. Doi: https://doi.org/10.1007/s11540-019-09449-6
590
G. Akdemir Evrendilek, B. Bulut, S. Uzuner Int J Agric Environ Food Sci 5(4):580-591 (2021)
Lambert, R.J.W., Skandamis, P.N., Coote, P.J., Nychas, G.-J.E. (2001). A study of the minimum inhibitory
concentration and mode of action of oregano essential oil, thymol and carvacrol. Journal of Applied
Microbiology, 91(3): 453-462. Doi: https://doi.org/10.1046/j.1365-2672.2001.01428.x
Li, G.-X., Liu, Z.-Q. (2009). Unusual antioxidant behavior of α- and γ-terpinene in protecting methyl linoleate,
DNA, and erythrocyte. Journal of Agriculture and Food Chemistry, 57(9): 3943–3948. Doi:
https://doi.org/10.1021/jf803358g
Liu, H., Xie, F., Yu, L., Chen, L., Li, L. (2009). Thermal processing of starch-based polymers. Progress in Polymer
Science, 34: 1348-1368. Doi: https://doi.org/10.1016/j.progpolymsci.2009.07.001
Liu, X., Wang, Y., Yu, L., Tong, Z., Chen, L., Liu, H., Li, X. (2013). Thermal degradation and stability of starch
under different processing conditions. Starch-Starke, 65: 48-60. Doi:
https://doi.org/10.1002/star.201200198
Lopez-Rubio, A., Fabra, M.J., Martinez-Sanz, M., Mendoza, S., Vuong, Q.V. (2017). Biopolymer-based coatings
and packaging structures for improved food quality. Journal of Food Quality, 7: 1-3. Doi:
https://doi.org/10.1155/2017/2351832
Mahomoodally, M.F., Zengin, G., Aladag, M.O., Ozparlak, H., Diuzheva, A., Jekő, J., Cziáky, Z., Aumeeruddy,
M.Z. (2019). HPLC-MS/MS chemical characterization and biological properties of Origanum onites
extracts: a recent insight. International Journal of Environmental Health Resources, 29(6): 607-621. Doi:
https://doi.org/10.1080/09603123.2018.1558184
Min, B.J., Oh, J.-H. (2009). Antimicrobial activity of catfish gelatin coating containing origanum (Thymus
capitatus) oil against gram-negative pathogenic bacteria. Journal of Food Science, 74: 143–148. Doi:
https://doi.org/10.1111/j.1750-3841.2009.01115.x
Moreno, O., Cárdenas, J., Atarés, L., Chiralt, A. (2017). Influence of starch oxidation on the functionality of starch-
gelatin based active films. Carbohydrate Polymers, 178: 147-158. Doi:
https://doi.org/10.1016/j.carbpol.2017.08.128
Murthy, M.S.R.C., Swaminathan, T., Rakshit, S.K., Kosugi, Y. (2000). Statistical optimization of lipase catalyzed
hydrolysis of methyl oleate by response surface methodology. Bioprocessing Engineering, 22: 35-39.
https://doi.org/10.1007/PL00009097
Nandane, A.S., Jain, R.K. (2018). Optimization of formulation and process parameters for soy protein-based edible
film using response surface methodology. Journal of Packaging Technology Research, 2(3): 203-210.
Doi: https://doi.org/10.1007/s41783-018-0045-2
Othman, S.H., Edwal, S.A.M., Risyon, N.P., Basha, R.K., Talib, R.A. (2017). Water sorption and water
permeability properties of edible film made from potato peel waste. Food Science and Technology, 37:
63-70. Doi: http://dx.doi.org/10.1590/1678-457x.30216
Ozdemir, M., Floros, J.D. (2008). Optimization of edible whey protein films containing preservatives for water
vapor permeability, water solubility and sensory characteristics. Journal of Food Engineering, 86(2): 215-
224. Doi: https://doi.org/10.1016/j.jfoodeng.2007.09.028
Park, S.B., Lih, E., Park, K.S., Joung, Y.K., Han, D.K. (2017). Biopolymer-based functional composites for
medical applications. Progress in Polymer Science, 68: 77-105. Doi:
https://doi.org/10.1016/j.progpolymsci.2016.12.003
Pathak, P.D., Mandavgane, S.A., Puranik, N.M., Jambhulkar, S.J., Kulkarni, B.D. (2018). Valorization of potato
peel: a biorefinery approach. Critical Reviews in Biotechnology, 38(2): 218-230. Doi:
https://doi.org/10.1080/07388551.2017.1331337
Peterson, J.D., Vyazovkin, S., Wight, C.A. (2001). Kinetics of the thermal and thermo-oxidative degradation of
polystyrene: polyethylene and poly(propylene). Macromolecular Chemistry and Physics, 202: 775-784.
Doi: https://doi.org/10.1002/1521-3935(20010301)202:6<775::AID-MACP775>3.0.CO;2-G
Quintavalla, S., Vicini, L. (2002). Antimicrobial food packaging in meat industry. Meat Science, 62: 373–80. Doi:
https://doi.org/10.1016/S0309-1740(02)00121-3
Razavi, S.M.A., Amini, A.M., Zahedi, A.Y. (2015). Characterisation of a new biodegradable edible film based on
sage seed gum: Influence of plasticiser type and concentration. Food Hydrocolloids, 43: 290-298. Doi:
https://doi.org/10.1016/j.foodhyd.2014.05.028
Rice, E.W., Baird, R.B., Eaton, A.D. (2005). Standard methods for the examination of water and wastewater, 23rd
ed. American Public Health Association, American Water Works Association, Water Environment
Federation.
Salleh, E., Muhammad, II., Pahlawi, Q.A. (2014). Spectrum activity and lauric acid release behaviour of
antimicrobial starch-based film. Procedia Chemistry, 9: 11-22. Doi:
https://doi.org/10.1016/j.proche.2014.05.003
Sevindik, E., Aydin, S., Kurtoglu, C., Tin, B. (2019). Evaluation of essential oil composition of Origanum onites
L. (lamiaceae) plant and antifungal activity on some strong pathogen fungi. Afs-Advances in Food
Science, 2019, 32-35
591
G. Akdemir Evrendilek, B. Bulut, S. Uzuner DOI: 10.31015/jaefs.2021.4.18
Seydim, A.C., Sarikus, G. (2006). Antimicrobial activity of whey protein based edible films incorporated with
oregano, rosemary and garlic essential oils. Food Research International, 39(5): 639-644. Doi:
https://doi.org/10.1016/j.foodres.2006.01.013
Simonin, H., Guyon, C., Orlowska, M., de Lamballerie, M., Le-Bail, A. (2011). Gelatinization of waxy starches
under high pressure as influenced by pH and osmolarity: Gelatinization kinetics, final structure and
pasting properties. LWT- Food Science and Technology, 44: 779–786. Doi:
https://doi.org/10.1016/j.lwt.2010.07.002
Soares, R.M.D., Lima, A.M.F., Oliveira, R.V.B., Pires, A.T.N., Soldi, V. (2005). Thermal degradation of
biodegradable edible films based on xanthan and starches from different sources. Polymer Degradation
and Stability, 90: 449–454. Doi: https://doi.org/10.1016/j.polymdegradstab.2005.04.007
Torres, J.A., Velazquez, G. (2005). Commercial opportunities and research challenges in the high pressure
processing of foods. Journal of Food Engineering, 67(1-2): 95-112. Doi:
https://doi.org/10.1016/j.jfoodeng.2004.05.066
Valero, M., Francés, E. (2006). Synergistic bactericidal effect of carvacrol, cinnamaldehyde or thymol and
refrigeration to inhibit Bacillus cereus in carrot broth. Food Microbiology, 23(1): 68-73. Doi:
https://doi.org/10.1016/j.fm.2005.01.016
Xu, J., Zhou, F., Ji, B.-P., Pei, R.-S., Xu, N. (2008). The antibacterial mechanism of carvacrol and thymol against
Escherichia coli. Letters in Applied Microbiology, 47(3): 174-179. Doi: https://doi.org/10.1111/j.1472-
765X.2008.02407.x
Top Related